The supersize lifestyles of the wealthy can leave a supersize carbon footprint. While some retailers indulge eccentric whims with products like bottled yacht fuel, other companies try to pamper their clients and the planet. An Australian tech company is developing a solar sail that will harness both wind and solar energy for use on large yachts. Solar Sailor estimates that on a vessel traveling at 18 knots, the solar element of the device could save roughly 5 percent in fuel consumption, while the wind power component could save another 20 to 40 percent. Now you know what to buy for the billionaire who has everything.